In many countries faced with an aging population, care of the elderly has become an important issue. The greater the number of bedridden elderly people in a society, not only the heavier burdens imposed on the elderly themselves and their families, but also in increased social cost. Therefore, movements to ensure QOL (quality of life) of the elderly and to encourage self-support by the elderly have become more prevalent.
Promoting self-support of the elderly requires, in addition to their strong desire to stand on their own, prophylactic medical approaches for preventing onset of various diseases.
Cardio-vascular diseases are commonly found among the elderly and frequently lead to bedridden lives, and pose serious problems to the aging population along with cancer. Arteriosclerosis, one of the major cause of cardio-vascular disease in geriatrics, often lead to ischemic heart disease, such as angina pectoris and myocardial infarct, and cerebral apoplexy such as cerebral infarction, cerebral hemorrhage or subarachnoidal hemorrhage.
With aging, certain degree of arteriosclerosis is developed in all. However, progress of arteriosclerosis may be retarded to some extent. That is, fatal damage to the arteries can be prevented by educational intervention concerning diet, exercise, and non-smoking as well as drug therapy and surgical intervention depending of the case.
However, in reality, convenient and precise diagnosis of artery conditions is not easy. At present, angiography is considered the best method for determining the condition of the artery. Since angiography is an invasive technique for the subject, method of diagnosis can only be applied to patients in serious condition of cardiovascular disease. Therefore, angiography cannot be employed primary screening method for detection of arteriosclerosis in asymptomatic patiens.
As an alternative to angiography, photographing of the eyeground; i.e., diagnosis on the basis of a photograph of the eyeground (hereinafter referred to as “eyeground-based diagnosis”), is employed as means for determining the conditions of arteries, particularly the cerebral arteries. Photographing of the eyeground is non-invasive to a subject, and can be performed conveniently. Therefore, this technique can be widely used in health monitoring checks and other types of medical examinations: Nonetheless, eyeground-based diagnosis has not necessarily been employed as general means for diagnosing arteriosclerosis.
A conceivable reason for the above is that standards for diagnosing arteriosclerosis on the basis of photo-captured images of the eyeground are very complicated, and correct and proper eyeground-based diagnosis requires considerable clinical experience. In contrast, pursuit of convenience in eyeground-based diagnosis fails to attain sensitive detection of arteriosclerosis. At present, arteriosclerosis is diagnosed from photographs of the eyeground on the basis of “standards proposed by the hypertension research group in the Ministry of Education in 1969,” “K-W classification,” or “Scheie's classification,” and over the years eyeground-based diagnosis has been gradually simplified. However, eyeground-based diagnosis has not yet become the first choice in clinical settings as some skill and experience is required.
In view of the foregoing, an object of the present invention is to provide non-invasive, simple and sensitive means for detecting arteriosclerosis.